Improvement in balancing millstones



G. S. THOMPSON. Balancing Millstones.

- Patented 'Nov. 23, 1869.

N. Ptrilm Prwbumo mr. Wnhingtnn. n c

waited Estates g am attire Letters Patent No. 97,134, dated November 23,1869.

IMPROVEMENT IN BALANCING MILL STONES.

The Schedule referred to in these Letters Patent and making part of thesame.

To all whom it may concern Be it known that I, GEORGE S. THOMPSON, ofthe ;e.ity and county of Philadelphia, and State of Penn- ;sylvania,have made certain Improvements in Mills for Grinding Grain,MineralSubstances, &c.; and I do hereby declare that the following is afull, clear, and exact description of the same, reference being had tothe accompanying sheet of drawings, and to the letters of referencemarked'thereon.

My invention consists in adjusting the upper stone of a mill, in whichthe lower stone is the runner, by the use and application of upper andlower adj ustingscrews, in connection with adjustable nuts, havingdovetailed tenons which take into corresponding mortises in the housingsof the same, whereby the upward pressure of the upper stone is preventedfrom spreading and cracking the housings.

\ On reference to the accoinpan yin g sheet of d rawin gs, making partof this specification Figure 1 is a perspective view, and

Figure 2 is an elevation of the housing.

Similar letters refer to similar parts in the several views.

A great drawback in mills for grinding, and which in a great measureaffects their etiicieucy, is the difliculty experienced in adjusting thestones at the proper distance apart, and balancing them to run perfectlytrue and even. I accomplish the operation of levelling and adjusting orsetting the stones at the requireddistance apart, by means of levellingadjustingscre-ws,-as follows: (As before stated, the lower stone is therunner, the upper one being fixed.)

A B are the upperandlower stones of a mill. The lower one turns withaspindlc, as usual; the upper one has a horn-band, O, shrunk on it.

This band has a suitable number, four being shown in this instance, ofhorns I), projecting from it, forearrying the stone.

These horns take into the slots E, of the housings F, on the table G-ofthe mill, and are carried on the ends of the upwardly-projecting screwsH, which take through correspondingly-tappcd openings in the crosspiecesa of the housing. The ends of the downwardlyprojecting screws K bear onthe upper sides of the horns, and are prevented from lifting by means ofthe nuts L in the slots E. The points ofthe horns, where the upper andlower screws bear, are recessed to stiffen the ends of the same.

To level and adjust theupper stone A, the top or downwardly-projectingscrews K are hacked or unscrewed, and the lower screws H either raisedor lowered by turning in the cross-pieces a, until the stone 7 isperfectly true and level, and set at the required distance from therunner-stone B. The jain-nutsM on the same screws are then screwedagainst the crosspiece a, to keep them from unscrewing, after which theupper screws K are screwed firmly on the top of the horns, to keep theupper stone from liftin".

The upward pressure of the stationary stone A is very great, and varieswith the grain or other article to be ground, the tendency of which,acting on the nuts L, through the horns D and the screws K, is to spreadthe sides or guides l) of the housings, when the flanges or projectionsof the nut are level, and bear squarely against the ledges orprojections c at the top of the guides, to prevent which, and makethehousingscapable of sustaining any upward pressure commensurate withthe size of the mill, 1 construct the nut L with dovetailed tenons d,which take into corresponding mortises e in the housings, so that whenthe pressure of the stone is brought upon the nut, the tenons will beforced firmly into the mortises, thereby keeping the sides or guides l)from-spreading apart and cracking at their intersection with thecross-piece a.

I am aware that mills have been constructed with one levelling andadjusting-screw foreach horn, as shown in the patents ot'J. Straub, May28, 1867, and H. I Straub, March 20,1866; anda rolling-mill, having apressure screw-nut with projecting flanges, is exhibited in the patentof Josiah Holmes, July 18, 1865, thertenon-and-mortise device not beingshown.

My invention is designed to tram or level and adjust the stones of amill, and, atthe same time, to correct the effect of the upward pressureof the upper stone.

\Vhat I claim as my invention, and desire to secure by Letters Patent,is-

The horns D, the upper and lower upwardly and downwardly-projectingscrews H K, the nuts L, with their tenons d, and the housings F, withtheir mortises e, substantially as shown and described.

In testimonywhereofil hereunto sign my name to this specification, inpresence of two subscribing wit- IIOSSGS.

GEORGE S. THOMPSON.

Witnesses:

FRANCIS D. PASTORIUS, J on: H. LIBBON.

